How do you reference JavaScript in latest gradle-intellij-plugin template?

I used github templating of gradle-intellij-plugin to create a new plugin that uses kotlin instead of groovy for gradle.

My. plugin needs the JavaScript plugin (to be used in IntelliJ Ultimate or WebStorm) and so I've set

platformType = IU

vs

platformType = IC

and then to reference the plugin I've tried:

platformPlugins = JavaScriptLanguage

platformPlugins = JavaScript

platformPlugins = com.jetbrains.intellij.javascript

and probably a few others and absolutely nothing works. No matter what I try, basically this is the error:

Cannot find builtin plugin JavaScriptLanguage for IDE: /Users/mark/.gradle/caches/modules-2/files-2.1/com.jetbrains.intellij.idea/ideaIU/2021.2/31f9496f635cec87427837101e04cbcddfb544d7/ideaIU-2021.2